In the riding coach on the auto train department, they pretty much divide people in the "Families from Hell" car, and the "Seniors from Hell" car, and the desirable young adults and adults car.
Once your kids are past the age of 11 or so, and if they are quieter types, then if you tell the seat assigner that your teenage children need to work on their thesis the whole way down, and would prefer a quieter car, then you can often work your way out of the family car.
If you have smaller children, there are some advantages to the family car, because you don't need to worry if your kids start doing loud kid stuff.
It's a hoot, because the seniors want away from the "noisy kids", but they make as much noise -- some of them -- complaining and squabbling as children do.